JPH0248505Y2 - - Google Patents

Description

[Detailed explanation of the invention] Industrial field of application This invention is used as part of on-site measurements to make predictive judgments about deformation and destruction of the soft ground when constructing embankments for facilities such as roads on soft ground. The present invention relates to an automatic measurement device for the amount of ground surface subsidence used for automatically measuring the amount of ground surface subsidence.
The present invention relates to an automatic measuring device for the amount of ground surface settlement that can be used to measure settlement that also serves as a soil survey using Swedish-style sounding or Dutch-style cone penetration testing.

BACKGROUND TECHNOLOGY Currently, the most popular and inexpensive measuring device for measuring the amount of ground subsidence is one that installs a subsidence plate 2 on the ground surface of soft ground 1 and connects it to the subsidence plate 2, as shown in Fig. 5. The settling rod 3 is vertically erected through a PVC pipe 7 buried in the embankment 4 so as not to receive resistance, and its top end is made to protrude above the upper surface of the embankment 4, and the level is measured using a leveling rod 5 and a level meter 6. be.

Conventionally, an automatic measuring device for the amount of ground subsidence shown in FIG. 6 has also been used. The rod 10, which is an immovable shaft, is buried until the screw anchor 8 at its tip reaches the support layer 9, and the rod 10 is protected by a friction cutter pipe 11 and connected to a sinking plate 12 installed on the ground surface. This configuration includes a subsidence gauge 13. When the subsidence plate 12 subsides along the rod 10 due to ground subsidence, the displacement is measured and recorded by the continuous subsidence meter 13.

Problems to be Solved by the Present Invention In the case of the measuring device shown in Fig. 5, it is difficult to automatically measure the amount of subsidence. In addition, since the settling plate 2 and the settling rod 3 are installed on the ground surface of the soft ground 1 prior to the construction of the embankment 4, and the settling rod 3 is made to protrude from the top surface of the embankment 4, this causes a major hindrance to the construction of the embankment 4. . In addition, if daily maintenance is not carried out sufficiently, the settlement rods 3 may be damaged during construction of the embankment 4, making it impossible to accurately measure the amount of ground settlement.

In addition, in the case of the automatic measuring device shown in FIG. 6, in order to bury the friction cutter pipe 11,
A hole of about φ200 (boring work) is essential.
Depending on the location, a very deep hole must be drilled, and the cost of drilling is high, so it has the disadvantage that it is too expensive to simply measure the amount of ground subsidence.

Therefore, the purpose of this invention is to be able to continuously and automatically measure the amount of ground subsidence without interfering with the construction of embankments 4, etc., and to be able to use it easily and inexpensively, without having to drill holes. Doesn't require any
Provides an automatic measuring device for the amount of ground surface settlement in soft ground that has an improved configuration that can also perform static penetration resistance measurements of in-situ soil similar to the Dutch double-pipe cone penetration test or the Swedish sounding test. It's about doing.

Means for Solving the Problems As a means for solving the problems of the above-mentioned prior art, an automatic measuring device for the amount of ground surface settlement on soft ground according to this invention is provided, as shown in FIGS. 1 to 4 of the drawings. As shown, the cone screw 20 is pushed vertically until it reaches the support layer 9 under the soft ground, and the cone screw 20 is inserted into the ground to transmit a constant rotational force and pushing force to the cone screw 20 when it penetrates. an inner pipe 21 as a rigid, immovable shaft that is connected to the cone screw and protrudes above the ground surface of the soft ground 1 through the middle pipe 22;
and a subsidence plate 25 installed on the ground surface of the soft ground 1.
The sensor section 26 is composed of the upper sensor section 26. In particular, the sensor section 26 is connected to the inner tube 21 which is the stationary shaft.
and a pulse counter 31 that measures the amount of ground surface subsidence by measuring the amount of relative movement with the subsidence plate 25 that subsides with the ground surface in units of linear length, and the upper end of the inner pipe 21. and sensor section 26
Each of these is characterized in that a protective box 27 is installed on the sinking plate 25 with a height sufficient to allow the upper end of the inner pipe 21 to protrude to protect it from the embankment 4.

In addition, in the automatic measuring device according to the present invention, the settlement plate 25 is provided with an outer tube 24 on its lower surface, which is longer than the ground surface settlement amount of the soft ground 1 and is slidably fitted to the upper end of the middle tube 22. Another feature is that the outer diameters of the cone screw 20 and the middle pipe 22 are the same dimensions as the JIS standard soil survey method (Swedish sounding or Dutch cone penetration test).

Operation The cone screw 20 is vertically penetrated into the soft ground 1 by applying a constant rotational force and pushing force to the middle pipe 22.

JIS outer diameter of cone screw 20 and middle tube 22
By using the same dimensions as the soil survey method determined by the standard (Swedish sounding or Dutch cone penetration test)
When the magnitude of rotational force and pushing force applied during penetration, penetration speed, depth, etc. are measured, the static penetration resistance of the in-situ soil is determined in exactly the same way as the so-called Dutch double tube cone penetration test or the Swedish sounding test. can be measured.

Since nothing is allowed to protrude from the surface of the embankment 4 (see Fig. 4), the embankment 4 can be constructed without any problems.

The amount of ground surface settlement of the soft ground 1 under the embankment 4 is determined by a pulse counter 31 or the like as the amount of subsidence (linear relative movement) of the settling plate 25 with respect to the rigid inner pipe 21, which is an immovable axis. It is a relatively simple and easily automatically measured unit of strength. In this way, the deformation of the soft ground 1 can be monitored in real time,
This contributes to accurate comprehensive predictive judgment regarding the destruction of soft ground 1.

Example Next, the illustrated embodiment of the present invention will be described.

FIGS. 1A to 1F show main installation process diagrams when the automatic measuring device for the amount of ground subsidence on soft ground according to this invention is used in a Swedish sounding mode.

In the figure, 20 is a cone screw, 21 is an inner tube connected to the cone screw 20, 22 is a middle tube that penetrates the cone screw 20, and 23 is a penetrating machine that applies rotational force and pushing force to the middle tube 22 for penetration.

As detailed in FIG. 2, the relationship between the cone screw 20 and the middle tube 22 is that they are arranged concentrically.
The claw portion 22a at the lower end of the middle tube 22 is connected to the cone screw 2.
It is configured to be able to detachably bite into the upper surface of the 0 and transmit rotational force in the engaged state.

The outer diameter of the upper surface of the cone screw 20 is φ33.3, and a screw groove for digging is formed on the outer periphery. An inner tube 21 is integrally fixed to the center of the upper surface of the cone screw 20 by welding or the like. The inner tube 21 is assumed to have strength and rigidity to maintain verticality and straightness as an immovable shaft, but its structure and material are not limited. It may also be a solid rod. The outer diameter of the inner tube 21 is about φ10.

The middle pipe 22 is a steel pipe with an outer diameter of about φ19, and has the strength to withstand the rotational force and pushing force penetrating the cone screw 20, and the rigidity to protect the inner pipe 21 from earth pressure so that it does not bend. There is.

The cone screw 20 and the inner tube 21 are combined with the inner tube 22 as shown in FIG.
For example, a pushing force of about 100 kg is applied to the material, and the material is rotated and penetrated vertically into the soft ground 1 (Fig. 1A).
Therefore, by measuring the penetration resistance value when the cone screw 20 penetrates, it is possible to conduct a soil investigation to determine the hardness, softness, compactness, or composition of the soil layer.

The cone screw 20 is penetrated until it reaches the support layer 9 below the soft ground 1 (FIG. 1B). When the support layer 9 is confirmed, only the middle pipe 22 is raised by a height h corresponding to the expected amount of ground surface subsidence (FIG. 1C). Moreover, the upper end of the middle pipe 22 is shortened by a length corresponding to the amount of ground surface subsidence, and is caused to sink below the ground surface of the soft ground 1. On the other hand, on the ground surface side of the soft ground 1, an outer pipe 24 is installed to protect the inner pipe 21, and also has a length corresponding to the amount of subsidence on the ground surface, and is slid telescopically against the middle pipe 22. It is fitted freely (Fig. 1D).

A subsidence plate 25 is installed on the ground surface of the soft ground 1,
The outer tube 24 is fitted onto the lower surface thereof. On the settling plate 25, the amount of relative movement in the vertical direction (ground surface settlement amount) between the settling plate 25, which sinks together with the ground surface of the soft ground 1, and the inner pipe 21, which is an immovable shaft, is measured in a linear manner. A sensor unit 26 is installed to measure the length in units of length.

For details of the structure of the sensor section 26, an example is given in the third section.
As shown in Figure A, a pair of rotatable rubber rollers 28, 28' are installed, sandwiching the inner tube 21, and one of the rubber rollers 28' and an angle sensor 29 (for example, an electromagnetic rotation detector) are installed. are connected in the same rotational relationship. In other words, the inner pipe 21
The amount of linear relative movement (amount of ground surface subsidence) in the vertical direction between the rubber roller 28' and the subsidence plate 25 is captured as the rotation of the rubber roller 28', and the rotation speed and rotation angle are converted into pulse outputs by the angle sensor 29 and sent to the ground. The amount of surface settlement is now being measured.

The sensor section 26 shown in FIG. 3B is connected to the inner tube 21.
Notches 30 are formed at regular intervals (pitch) in the axial direction (vertical direction) of the inner tube 21 and the sinking plate 2 by a pulse counter 31 that contacts the notches 30.
5 in the vertical direction (ground surface subsidence) is measured as the number of increments (number of pulses). As an alternative to the notches 30, a magnetic scale may be attached to the inner tube 21 and the scale may be detected by a magnetic pulse counter.

The reference numeral 27 in FIG. This is a steel protective box installed on the sinking plate 25. The upper end surface of this protective tube 27 is closed so as to withstand earth pressure. The protection box 27 has a height that is still slightly larger than the maximum (or final) amount of ground surface settlement of the soft ground 1.

According to the automatic measuring device for ground surface settlement with the above configuration, when the ground surface of the soft ground 1 subsides due to the construction of the embankment 4 or due to other causes, the subsidence plates 25 installed on the ground surface will coalesce. Since it sinks and a relative movement (displacement) occurs between it and the inner pipe 21, which is an immovable shaft,
The amount of displacement is determined by the sensor unit 26 as the amount of ground surface subsidence.
It is measured automatically and continuously.

Therefore, as shown in FIG. 4, the above automatic measuring device is installed directly under the embankment 4, and an automatic measuring device 40 for underground displacement and an automatic measuring device for ground surface displacement are installed on the sides of the embankment 4. 41, and each output is sent to the field office 44 through an interface 42.
Processing device 43 (personal computer)
Ground deformation can be monitored in real time by inputting data into the . Therefore, extremely detailed and highly accurate data can be obtained, contributing to comprehensive predictive judgment regarding the destruction of the soft ground 1.

Effects of the present invention The automatic measuring device for the amount of ground subsidence on soft ground according to the present invention allows the cone screw 20 to be vertically inserted into the soft ground 1 by applying a constant rotational force and pushing force to the middle pipe 22. Since it is penetrated and does not require any drilling (boring work), it can be implemented at a very low cost including construction and material costs, and is easy to use. Furthermore, the process of installing the automatic measuring device is simple, and labor can be significantly reduced.

Moreover, by making the outer diameters of the cone screw 20 and the middle pipe 22 the same as those of the soil survey method (Swedish sounding or Dutch cone penetration test) determined by JIS standards, the rotational force and indentation applied when the cone screw 20 penetrates By measuring the magnitude of force, penetration speed, depth, etc., it is possible to measure the static penetration resistance of in-situ soil in exactly the same way as the so-called Dutch double tube cone penetration test or Swedish sounding test. .
That is, there is the convenience of being able to conduct a soil survey to determine the hardness, softness, compactness, and composition of the soil layer.

In addition, since nothing protrudes from the surface (upper surface) of the embankment 4, the embankment 4 can be constructed without any problems, and it is convenient to use the embankment 4 as a road or the like.

Furthermore, the amount of ground surface settlement of the soft ground 1 under the embankment 4 is expressed as the amount of linear relative movement between the inner pipe 21, which is an immovable axis, and the settling plate 25, and is expressed in units of linear length in the sensor unit 26. Since automatic measurement is performed continuously with high accuracy, the sensor unit 26 can be simply configured with a pulse counter 31, etc., and the amount of ground subsidence required for destruction prediction analysis can be determined more quickly and accurately, and the amount of time required for measurement is reduced. Significant savings can be achieved.
Since the deformation of the soft ground 1 can be monitored in real time, it greatly contributes to the accuracy of comprehensive predictive judgment regarding the destruction of the soft ground 1.

[Brief explanation of drawings]

Figures 1A to 1F are explanatory diagrams showing the installation process of the automatic ground subsidence measuring device according to this invention, Figure 2 is an elevational view showing the configuration of the main parts enlarged, and Figure 3A , B is an enlarged view showing different configurations of the sensor section, Figure 4 is a schematic diagram showing a comprehensive ground measurement system, and Figures 5 and 6 are conventional ground surface subsidence measurement devices. FIG. 1... Soft ground, 9... Support layer ground, 20...
Cornscrew, 22...middle tube, 21...inner tube,
26...Sensor part, 27...Protective box, 25...
Subsidence plate, 31...Pulse counter.

Claims (1)

[Claims for Utility Model Registration] [1] A cone screw that is pushed vertically until it reaches a support layer under soft ground, and a cone screw that transmits a constant rotational force and pushing force to the cone screw when it penetrates into the ground. A middle pipe inserted therein, an inner pipe as a rigid immovable shaft that is connected to the cone screw and protrudes above the ground surface of the soft ground through the middle pipe, and a subsidence plate installed on the ground surface of the soft ground. The sensor part is a pulse counter that measures the amount of relative movement between the inner pipe, which is the immovable shaft, and the sinking plate that sinks with the ground surface in units of linear length, and calculates the amount of ground surface subsidence. etc., and that a protective box of a height that allows the inner pipe to protrude is installed on the sinking plate in order to protect the upper end of the inner pipe and the sensor part from the embankment. An automatic measuring device for the amount of ground subsidence in soft ground. [2] The sinking plate described in claim 1 of the utility model registration claim is provided with an outer pipe on its lower surface that is longer than the amount of ground subsidence and is slidably fitted to the upper end of the middle pipe. An automatic measuring device for the amount of ground subsidence on soft ground. [3] The outer diameter of the cone screw and the inner pipe described in item 1 of the claims for utility model registration shall be the same as the JIS standard soil survey method (Swedish sounding or Dutch cone penetration test). An automatic measuring device for the amount of ground subsidence on soft ground, which is characterized by: